GAP Bulletin Number 5
June 1996

The Ecological Society of America's Vegetation Classification Panel

Changes in the natural resources fields (e.g., a shrinking natural resources base, societal shifts in values, etc.) are resulting in demand for an "ecosystems" approach to research, planning, and management (Jennings 1995). Yet, until recently, there was not a consistent set of defined categories for naturally occurring assemblages of species (Orians 1993) that can be reliably used as building blocks for characterizing ecosystems at alpha, beta, delta, and gamma scales of diversity (sensu Whittaker 1960, 1977). There has never been as much land cover mapping activity in the U.S. as there is today. Although the GAP state projects are the principal source of the increase, GAP overall is but one of several major efforts. With all this activity, the development of a broadly accepted classification system that is maintained within a scientific peer-reviewed arena and recognized by government agencies is critical.

At the Ecological Society of America's (ESA)1994 meeting, an ad hoc group of members met to discuss the circumstance of and need for a standardized vegetation classification system. This led to the establishment by ESA of a standing panel on vegetation classification, made up of about 20 ESA members and several nonmember experts. The panel is working under the aegis of and with staff support of the ESA Sustainable Biosphere Initiative (SBI).

The panel's mission is to provide a standardized, scientifically credible North American vegetation classification system, given the following objectives:

  • provide a neutral forum for the review and discussion of vegetation classification;
  • set standards for hierarchical structure, nomenclature, and definitions for a North American vegetation classification;
  • establish a process for modifying the system as knowledge advances;
  • establish a peer-review process for recognizing natural communities and natural community alliances;
  • identify areas for further research and development;
  • provide broad public access to a standardized North American vegetation classification system.

The panel held its first full meeting at the 1995 conference of the International Association for Vegetation Science and began by reviewing the standards being proposed by the Federal Geographic Data Committee's Subcommittee on Vegetation Classification (FGDC-VC). In summary, the ESA panel suggested that FGDC-VS adopt the following language regarding purpose and policy:

"The purpose for these standards is to foster consistency, precision, and clarity in the structure, labeling, definition, and application of a systematic natural land cover taxonomy for the United States. Consistency, precision, and clarity are critical for effective and efficient decisions about resources where the focus is on complex natural assemblages of biotic organisms.

These standards are intended for use by both federal agencies and other user groups, including those engaged in land use planning or management by county and state governments, teaching or research, and uses by the private sector. Widespread use of these standards will facilitate integration of land cover data collected by diverse users into a common national database, enhancing utility beyond single projects and establishing a long-term framework for the nation's natural land cover information."

The ESA panel went on to comment on and suggest changes to the assumptions, guiding principles, definitions, structure, requirements, and procedures for reaching closure on standards that were then being proposed by FGDC-VS.

At the panel's last meeting (March 17-19) agreement was reached to propose that ESA take lead in establishing the following:

  • a standardized terminology for the floristically-based taxonomy and classification of natural communities and alliances of natural communities;
  • a database network for all available plot and stand data from which statistical descriptions of natural communities and alliances can be compiled;
  • a peer-review process for recognizing the names and attributes of natural communities and alliances, resulting in a brief standardized monograph for each type.

Descriptions of each of these components are now being developed and will be presented to the general membership at the annual ESA conference in August. For more information, contact Bruce Kahn at the SBI at or call (202) 833-8748.

Literature Cited

Jennings, M.D. 1995. A confluence of biology, ecology and geography for the management of biological resources. The Wildlife Society Bulletin 23:658-662.

Loucks, O.L. 1996. 100 years after Cowles: A national classification for vegetation. Bulletin of the Ecological Society of America 77:75-76.

Orians, G.H. 1993. Endangered at what level? Ecological Applications 3:206-208.

Whittaker, R.H. 1960. Vegetation of the Siskiyou mountains, Oregon and California. Ecological Monographs 30:279-338.

Whittaker, R.H. 1977. Species diversity in land communities. Evolutionary Biology 10:1-67.

Michael D. Jennings, National Coordinator
Gap Analysis Program
Moscow, Idaho

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